I have a Dida Mobile data sim which uses the Three network (18GB over 6 months for £20). I normally use it in a MiFi but want to use it in my new iPad 4G.

In my iPhone 4s I can insert this SIM and setup (and use) Personal Hotspot. In my new iPad the Personal Hotspot option is completely missing even thought the DiDa Mobile internet is working (I can browse web pages etc).

So, I tried 'Reset Network Settings' and other things I can think of... nothing.

I have a Dida Mobile data sim which uses the Three network (18GB over 6 months for £20). I normally use it in a MiFi but want to use it in my new iPad 4G.

In my iPhone 4s I can insert my SIM and setup (and use) Personal Hotspot. In my new iPad the Personal Hotspot option is completely missing even thought the DiDa Mobile internet is working (I can browse web pages etc).

So, I tried 'Reset Network Settings' and other things I can think of... nothing.

Can anyone if the UK see the option?

Does your carrier support the Hotspot feature? It is carrier dependent.

I've been on the phone with Three today to chase this up.
I too wanted to use the personal hotspot feature.
Their technical support teams are still claiming that it is not actually possible to use the iPad as a personal hotspot - they don't seem to be aware that the new iPad (iPad 3) DOES have that as a feature.
I've argued it out each time, and each time they say no it doesn't...
I'm currently on hold after telling the 3rd or 4th person that it sure does have a personal hotspot feature.

Methinks they've overlooked this one.

I'll let you know how I get on...

Edit:
Forgot to say, they keep telling me that I can add on a tethering add-on, yet when I try they say it's not possible.

Edit:
Off the phone now.
That haven't got a clue. They weren't aware that the feature has been added to the iPad 3. This one had to go google personal hotspot to see where it should be...
She said I need to speak to apple to ask them about it because Three don't have the settings.
Yet she also agreed that she should escalate it to get somebody higher to look into it to get their carrier settings updated.
I've asked for her to keep me updated on whether I'd be able to use personal hotspot feature or not... I don't expect they will.

Edit:
I've tried my sim in my iPhone 4S and sure enough, Personal Hotspot shows up in settings. Both underneath wi-Fi, and in General-Network.
Surely this means Three need to update the carrier settings for the iPad?

I have a Dida Mobile data sim which uses the Three network (18GB over 6 months for £20). I normally use it in a MiFi but want to use it in my new iPad 4G.

In my iPhone 4s I can insert this SIM and setup (and use) Personal Hotspot. In my new iPad the Personal Hotspot option is completely missing even thought the DiDa Mobile internet is working (I can browse web pages etc).

So, I tried 'Reset Network Settings' and other things I can think of... nothing.

I also called Three yesterday, but I was told that my 15GB per month data plan does permit tethering and that Three have put no restrictions on the new iPad so it should work. However, as we all know, it doesn't. The Three representative insisted that it is nothing to do with them and I should contact Apple. I asked if some new carrier settings needed to be sent - but the Representative said that this was not necessary.

I duly called Apple support and waited nearly 30 minutes to get through due the 'large call volumes' and no sooner than a human answered, I was cut off. I will try again on Monday.

My belief is that, despite what Three told me, a new carrier setting needs to be sent by Three and this is not something Apple can sort out.

I also called Three yesterday, but I was told that my 15GB per month data plan does permit tethering and that Three have put no restrictions on the new iPad so it should work. However, as we all know, it doesn't. The Three representative insisted that it is nothing to do with them and I should contact Apple. I asked if some new carrier settings needed to be sent - but the Representative said that this was not necessary.

I duly called Apple support and waited nearly 30 minutes to get through due the 'large call volumes' and no sooner than a human answered, I was cut off. I will try again on Monday.

My belief is that, despite what Three told me, a new carrier setting needs to be sent by Three and this is not something Apple can sort out.

I think you're right, new carrier settings are needed.
I had such a difficult time asking them to add a tethering allowance to my plan, for an extra £5 just so I could test if something updated.
The fact that personal hotspot shows with the same sim in an iPhone 4S makes me think the same, that the carrier settings need updating.
I think Three may have to request that with apple? Not sure.. I'll be on the phone to Three again tomorrow or Monday to see if I can at least get them to add the tethering add-on so I can go back and say look... Doesn't work. Will end up going the complaints route cos they sold me something saying it would work and it didn't, then hopefully they'll pay more attention :-)